1. Field of the Invention
The present invention generally r lates to an optical code reader and a process for reading optical codes, and particularly, to a portable optical code reader using a laser beam and a process for reading optical codes using the optical code reader.
2. Description of the Related Art
Recently, a control of commodities using an optical mark such as a bar code has been widespread among retail stores of many kinds. Accordingly, a demand for a system such as a point-of-sale (POS) system which is necessary for such control of commodities has increased.
In the POS system, an apparatus for reading optical marks such as a bar code reader for reading bar codes have been widely used, and as kinds of commodities dealt with has increased, demands for a bar code reader which may handle such a variety of commodities have also increased.
A so-called "bar code menu" is a list of bar codes, each of which corresponds to a commodity or good onto which a bar code cannot be attached for reasons such as appearance problem or heaviness, and is usually printed onto a sheet of plastic-type paper. For such a bar code menu, a pen-type bar code reader or a touch-scanner which is portable are currently used and are brought directly above a bar code to read. However, one of the problems associated with such portable apparatus is that the length of a scanning beam generated from the apparatus is relatively short.
On the other hand, a bar code reader using a laser beam, which is commonly used by a cashier in a supermarket, etc., is characterized by its long length of the scanning beam and therefore the bar code reader is capable of reading a bar code attached to a commodity even if the commodity is some distance away from a reading site of the apparatus.
A development which has been achieved recently is that the above-mentioned two functions are combined in a bar code reader. That is, the bar code reader is fixed by using, for example, a holder when reading a bar code attached to ordinary goods, and it is released from the holder and used as a portable bar code reader when reading a "bar code menu" or a bar code attached to goods which cannot be moved.
However, since the scanning beam generated from such a bar code reader can reach a relatively long distance, the bar code reader often reads bar codes which are located in the vicinity of an objective bar code in a "bar code menu" as well. Also, since the bar code reader keeps generating a scanning beam even when used as a portable bar code reader, it reads every bar codes, including the ones that are not required to be read, over which it passes during a transfer from one to the other.
If the length of the scanning beam is shortened in order to avoid the above-mentioned problems, the possibility of such accidents cannot be eliminated completely but also the bar code reader may not be used as a fixed apparatus.